On the other hand, what is the reasonable way of action here? A whole set of acquaintances grieving for days about a person only one of them knew? Next to this being quite detrimental to productivity (and you can argue all day about how bad we have it in this society), it would just lead to us being in a mostly permanent state of grieve, as there will always be someone that had some shocking event in recent times, for any reasonably large set of people.